title: 3d early transition metal complexes supported by a new sterically demanding aryloxide ligand.
abstract: The bulky aryloxide 2,6-bis(diphenylmethyl)-4-tert-butylphenol [HOAr(tBu)] (1) can be synthesized from 4-tert-butylphenol and benzhydrol in solvent-free conditions and obtained pure in 91% yield. Deprotonation of HOAr(tBu) is accomplished with M(N(SiMe3)2) (M = Na, Li), yielding the corresponding salts of the aryloxide [MOAr(tBu)] (M(+) = Na (2), Li(3)) in 83% and 73% yield, respectively. Facile salt formation of the aryloxide ligand allows for transmetalation to a variety of metal halides. Through transmetalation reactions involving two aryloxides, mononuclear complexes of the type [M'(OAr(tBu))2Cl(THF)2] (M' = Sc (4), V (5), Cr (6), Ti (7)) can be prepared from the corresponding metal halide precursor MCl3(THF)3. Additionally, two aryloxides can be coordinated to Ti(IV) via a protonolysis route of Ti(NMe2)2Cl2 and 2 equiv of HOAr(tBu) to yield [Ti(OAr(tBu))2Cl2(NHMe2)] (8) in 72% isolated yield. Single-crystal X-ray diffraction studies of 1, 2, and the 3d metal complexes 5-8 clearly show the steric demand of the bulky ligand, whereas in transition metal complexes we do not observe the formation of mononuclear tris-aryloxide complexes.
authors.affiliation: Department of Chemistry and the Molecular Structure Center, Indiana University , Bloomington, Indiana 47405, United States.
authors.forename: Keith
authors.initials: K
authors.lastname: Searles
authors.forename: Ba L
authors.initials: BL
authors.lastname: Tran
authors.forename: Maren
authors.initials: M
authors.lastname: Pink
authors.forename: Chun-Hsing
authors.initials: CH
authors.lastname: Chen
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Mindiola